Various tools exist for identifying locations in communications networks that are causing performance problems, such as communication Quality of Service (QoS) problems. An illustrative example thereof is the “Blame Expert” tool of Avaya Inc. that is described in U.S. Pub. No. US 2005/0053009. Like other tools of its kind, the Blame Expert tool analyzes network traffic measurements and network topology information to identify potentially-faulty links in the network as a whole.
Tools that actively test a network introduce traffic into the network to run the tests. One such tool is the ExpertNet™ VoIP quality management tool, a.k.a. EQM, of Avaya Inc. This tool simulates VoIP calls in a customer's network and collects quality-of-service measurements on those test calls. However, network managers are sensitive to the amount of traffic that such tools add to the network, and they want to minimize the amount of test traffic so that users are not affected by reduced network bandwidth and network congestion.
Some algorithms and means of displaying data require “snapshots” of a network, and they need to collect as much data as possible in a short time. For instance, the abovementioned Blame Expert tool which attempts to pinpoint problems in a network, requires that all test calls finish within 5 minutes. The Blame Expert tool works best when it has the results for many test calls, but system and network resources constrain the number of test calls that can reasonably be made.